THE QUESTION OF THE TOXICITY OF DISTILLED WATER 4OI 
First, there is the problem of adjustment. Some organisms because 
of their inherent physiological characteristics possess a low order of 
resistance to harmful agents and are injured, sometimes fatally, by 
slight deviations from optimum conditions. However, in the case of 
lupine seedlings a slow process of adjustment or acclimatization to 
distilled water fits them better for life within it than if they were 
thrust into the water immediately. That the change from tap water 
or culture solution, whatever it may be, to distilled water is great, 
can be demonstrated by the determination of the electrical conduc- 
tivity of the waters. It appears that such marked differences disturb 
the equilibrium between the physical and chemical functions of the 
organism. Several experiments were made and one was reported 
to test the theory of adjustment. The conclusion was reached that 
better root growth was obtained in distilled water when changes from 
tap to distilled water were made gradually rather than suddenly. 
This problem of adjustment is so important that it must be taken into 
account in all cultural work. 
The second aspect of the distilled water question dealt with in 
this paper is that of toxic root excretions. The idea that roots of 
plants excrete injurious substances, harmful to their further growth, 
has persisted from the time of De Candolle. The investigations of 
the Bureau of Soils of the U. S. Department of Agriculture appear 
to set this theory on a more secure foundation. In this paper are 
reported the results of experiments to show that, in all probability, 
seedling roots of Lupinus alhus excrete a substance that inhibits 
growth. The toxin was not isolated from the turbid solution but it 
was shown that when the water was changed four times daily the 
growth rate of the roots increased. Roots that had grown continually 
in distilled water presented the appearance of roots injured by dilute 
solutions of toxic salts. The roots were thick, short, more or less 
blunt and crooked near the tip, when grown continually in unchanged 
distilled water. In tap water the roots were long, slender, firm and 
usually straight. The lateral roots appeared later in tap water than 
in distilled water. 
Michigan Agricultural College, 
Experiment Station, 
East Lansing, Michigan 
